“…Fifteen studies involved nulliparous participants [23, 24, 26, 27, 29, 31, 35, 37-39, 41, 42, 44, 45, 53] and 15 studies included both nulliparous and parous participants [8, 25, 28, 30, 32-34, 36, 40, 43, 46, 48, 50-52]. Two studies did not report information on parity of participants [47,49].…”